LET us all take the pressure off Kellen Clemens right here and now on the first day of the rest of his career and guarantee that he will not be The Next Joe Namath.

He will not show up today against a well-regarded defensive coordinator named Gregg Williams and laugh in the face of a heavy blitz and yawn and light up the scoreboard.

Vince Young has regressed in his second season and disabled Matt Leinart had taken a step back and Jay Cutler is playing through growing pains, and here comes Kellen Clemens taking over for Chad Pennington and starting his second game in the NFL.

No one should expect miracles, or the start of a green-and-white fairy tale that will wind up with the kid getting a pantyhose commercial.

But Chad Pennington didn’t have enough arm to carry everyone drowning around him to safety, and with the Patriots in a league of their own, it is clearly time for Eric Mangini to find out whether Clemens is the rocket quarterback who can eventually withstand the icy stare of Bill Belichick and not blink should he find himself in a gunslinger shootout next season and beyond with Tom Brady.

Clemens stands as the Hope Diamond for a franchise desperately in need of hope, and playmakers, and toughness in the trenches on both sides of the ball.

So today isn’t about today as much as it is about tomorrow.

To all you long-suffering Jets fans since Super Bowl III, be patient with me when I urge patience with Kellen Clemens.

The O’Brien Era started in 1984. O’Brien, drafted ahead of Dan Marino in 1983, has some advice for Clemens.

“I would say, ‘Think about what you’ve wanted to do, and why you want to it.’ I don’t know anybody who says, ‘I want to be a backup quarterback in the NFL,'” O’Brien said. “You want to be The Guy. Every kid in America, that’s what you want to do. And you’ve gotta believe in yourself that you’re gonna get the job done because if you don’t, nobody else is. And just go out and let it fly. Don’t dwell on the bad things; dwell on the good things. It’s a lot better life that way.”

It was the season when Vinny Testaverde ruptured his Achilles on Opening Day, after Rick Mirer could not hold the fort, when Bill Parcells walked in on a gloomy Monday morning to address his sagging 1999 Jets.

“See that kid in the front pew?” Parcells said. “I don’t care if we lose the rest of our games, we’re going with him.”

And when Ray Lucas marched downstairs, there were Depends waiting for him at his locker. And now a new babe shall lead them eight years later.

What should Jet fans expect from Clemens?

“Laser-beam arm,” Lucas was saying. “Very mobile in the pocket … great pocket presence, but not afraid to run. Chad could get you into the right play; Kellen’s gonna take a little time. He can only get there from game-time experience. There’s a lot of things wrong right now with the Jets. They haven’t played four quarters at all in one game yet. Kellen Clemens is not the answer for everything.”

Lucas, after suffering a sprained ankle that briefly sidelined him, rallied the Jets to an 8-8 finish in Parcells’ last season on the sidelines in New York, but was back on the bench the next season when Testaverde returned and Pennington was a No. 1 draft choice. Lucas, a rising star these days on SNY, advises Clemens to make sure that one bad play does not become two bad plays.

“Like Parcells used to say, ‘Have that quarterback amnesia,'” Lucas said. “Everything’s not gonna go right. As long as you’re cool with that, just keep it moving.”

From his California perch, O’Brien observed Clemens at Oregon.

“I liked his leadership,” O’Brien said.

The kid is the only reason to watch the Jets.

“He can definitely [bleepin’] play,” Lucas said. “They didn’t draft him that high [second round] for him to be a disappointment.”